This invention relates to an improvement on a mold exchanging device for a blow molding apparatus, particularly to a counter measure to shorten time required for exchanging molds.
Conventionally, in the case where tubular plastic articles, such as plastic containers, are blow molded, parison pushed out of an extrusion head is caught by a mold of a blow molding apparatus and air is let in the parison by working an air blowing means comprising a pre-pinchers, an air nozzle, etc., arranged below the mold.
When exchanging molds, a carrier is moved between below a mold fitting position of the blow molding apparatus and a mold carrying in and out position, and a mold detached from the blow molding apparatus are loaded on the carrier, and carried out, and a new mold loaded on the carrier is carried in.
However, the conventional blow molding apparatus is provided with an air blowing means below a mold, so that a carrier's operation of carrying in and out the mold is impeded at the time of exchanging molds. Therefore, when exchanging molds, the air blowing means has to be detached from the blow molding apparatus, and another air blowing means suitable to the mold is attached to the blow molding apparatus, and then adjusted. Consequently, it has been a problem that many hours are required for exchanging molds because of the required time for detaching, attaching and adjusting the air blowing means.